Long Term Evolution (LTE) is a technical standard developed by the 3rd Generation Partnership Project (3GPP) organization. In an LTE system, duration of one subframe is 1 ms, and each subframe is equally divided into two slots, where duration of each slot is 0.5 ms. In the LTE system, a transmission time interval (TTI) is duration of one subframe.
In a wireless communications system, a latency is one of important factors affecting user experience. During uplink transmission in the LTE system, after receiving physical uplink shared channel (PUSCH) information, a base station needs to feed back a reception result to a terminal device after a specific time. For example, an acknowledgement (ACK) character is fed back when reception is correct, or a negative acknowledgement (NACK) character is fed back when reception is incorrect. If each data packet is sent in one subframe, the base station spends a relatively long time decoding the data packet. In addition, if reception of the data packet is incorrect, a minimum time interval between retransmission of the data packet and initial transmission of the data packet is also relatively long. This leads to a relatively long data transmission latency, affecting use experience of a user.